Such processes are used to condition the patients in terms of their heat states and optionally also their humidity states in devices used for thermotherapy, especially in incubators for premature and full-term newborn babies. To do so, body temperatures are measured and corresponding conditioning means, especially heating means, are actuated depending on the result.
A process of this class is described in DE 39 30 363 C2, wherein sensors, which are in connection with the body or with the ambient atmosphere for determining the actual values of the state and whose output values are sent to a data processing unit and these values are processed by the said data processing unit into correcting variables for influencing the operating parameters, are provided for controlling the operating parameters that determine the heat balance of a patient introduced into an incubator. It has also been known from the process of this class that at least two of four temperature sensors are provided for different body temperature zones, and the output values of these sensors are sent to the data processing unit and are compared with preset values there, so that a heating means is actuated in the incubator in the case of deviations in order to reach the desired temperature.
Thermotherapy devices, especially incubators, have hitherto been used in practice, which compare only one measured skin temperature with a set point and use the result directly as a controlled variable.
It has been known from clinical studies that two true body temperatures, namely, the core temperature and the peripheral temperature, are important for evaluating the state and the heat balance of a patient.
For example, undercooling can be recognized in the case of highly premature or full-term newborn babies already from an intense cooling of the periphery, while the core of the body is still in the normal range. The body attempts to maintain the core temperature by throttling the blood flow to the periphery, thus reducing the heat loss to the environment there.
Similarly, an increasing fever can be recognized from a decrease in the peripheral temperature with rising core temperature of the body. The body has centralized the blood flow to the core in this case in order to heat it to a higher temperature, and it throttles the blood flow to the periphery in order to save heat and to use it to heat the central organs.
A subsiding fever is recognized from a high core temperature of the body with a simultaneously high peripheral temperature. The body uses the large body surfaces of the periphery to cool the core of the body by a corresponding release of heat.
One drawback of all the prior-art processes for controlling incubators follows from the fact that the temperatures measured at the patient are measured on the skin surface and are therefore distorted by external effects, e.g., especially air flows, so that the operating conditions of the incubator are also set only incorrectly by means of incorrectly determined correcting variables.